I generally only use the ampersand when I'm calling a subroutine via a reference. The rest of the time, I follow perlstyle and put parenthesis on user-defined subroutines, even when I pass an empty argument list.

Idiomatic Perl is good, but I haven't seen enough people using the &subname-passes-@_ behavior often enough to use it regularly.

When putting a smiley right before a closing parenthesis, do you:

Use two parentheses: (Like this: :) )
Use one parenthesis: (Like this: :)
Reverse direction of the smiley: (Like this: (: )
Use angle/square brackets instead of parentheses
Use C-style commenting to set the smiley off from the closing parenthesis
Make the smiley a dunce: (:>
I disapprove of emoticons
Other